From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lee Jones <lee.jones@linaro.org>
Subject: Re: [PATCH v2 05/11] mfd: devicetree: bindings: Add Qualcomm SMD
 based RPM DT binding
Date: Mon, 27 Jul 2015 08:29:18 +0100
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To: Mark Brown <broonie@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@sonymobile.com>, "bjorn@kryo.se" <bjorn@kryo.se>, Andy Gross <agross@codeaurora.org>, Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Kumar Gala <galak@codeaurora.org>, Samuel Ortiz <sameo@linux.intel.com>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>
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On Fri, 24 Jul 2015, Mark Brown wrote:

> On Fri, Jul 24, 2015 at 11:24:34AM +0100, Mark Brown wrote:
> > On Fri, Jul 24, 2015 at 10:58:47AM +0100, Lee Jones wrote:
> > > On Thu, 23 Jul 2015, Mark Brown wrote:
>=20
> > > > I have no idea what's going on here, sorry.  I've not been read=
ing this
> > > > thread.
>=20
> > > All of the information you need is in the email you replied to.
>=20
> > The mail appears to have an edited down section of what looks like =
an
> > example rather than the actual binding.  I haven't seen the binding=
 so I
> > can't really comment on it.
>=20
> I managed to find the binding but I'm afraid I'm still not sure what =
the
> concern here is - can someone please be specific about the question(s=
)
> you're looking for an answer on?

[...]

=46rom here:

> > > > > +                pm8941-regulators {
> > > > > +                        compatible =3D "qcom,rpm-pm8941-regu=
lators";
> > > > > +                        vdd_l13_l20_l23_l24-supply =3D <&pm8=
941_boost>;
> > > >=20
> > > > I'd like Mark to glance at this.

Mark: Is this new property okay?

> > > > > +                        pm8941_s3: s3 {
> > > > > +                                regulator-min-microvolt =3D =
<1800000>;
> > > > > +                                regulator-max-microvolt =3D =
<1800000>;
> > > >=20
> > > > Aren't these fixed regulators?
> > >=20
> > > In this system configuration most of the regulators have fixed va=
lues,
> > > but the regulators (hw) are not fixed.
> >
> > I'm not sure that's how it works.  I believe 'max' and 'min' should
> > describe the upper and lower constraints of the regulator.  The act=
ual
> > value it runs it is selected elsewhere.
>=20
> The specified range of the regulator is 1.75-1.85V and this is handle=
d
> by the implementation, however the board designers have stated that i=
t
> is only allowed to be configured to 1.8V.
>=20
> So DT is used to narrow the capabilities of the individual component =
to
> something that's suitable for this particular system.
>=20
> > We still need Mark to look at this.

Is it okay for the regulator-{min,max}-microvolt to be artificially
restricted to the required value, despite knowing that the regulator
is capable of supply {more,less} voltage?

--=20
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org =E2=94=82 Open source software for ARM SoCs
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